Avoiding disturbing reflections on screens or other tilted visual tasks is possible through the same measures as described above. For the luminance limitation of luminaires, particular requirements apply.
Reflected glare on display screens
The better the anti-reflection coating of the screen, the higher the admissible luminance of luminaires and surfaces capable of reflecting on the screen. Current screen technologies allow for higher luminance values than past devices. For screens with positive polarity and with usual requirements regarding colour and detail of the information displayed e.g. in offices, places of education etc., higher luminance limits are defined in EN 12464-1 for luminaires capable of reflecting on the screen. For screens with high background luminance (> 200 cd/m2), the average luminance of the luminaires must not exceed 3.000 cd/m2. For screens with average luminance (< 200 cd/m2), the maximum of 1.500 cd/m2 applies. As actual measurements have demonstrated, usually background luminance values of < 200 cd/m2 are set in offices, with laptops even < 100 cd/m2, which means that the limit value of 1.500 cd/m2 applies. For details see chapter "Illumination of offices and rooms with VDU workstations".
The limit values apply for screens which are tilted at up to 15°, for a distribution angle from 65° and for all viewing angles surrounding the luminaire.
For luminance limit values for screens with negative polarity e.g. in CAD construction offices as well as further details on this matter see Chapter "Offices and rooms with VDU workstations".